Does this still work?

Hey guys, does this work with the latest version of WP (5.6)? Your plugin is recommended in the O’Reilly book ‘Building Web Apps with WordPress’ but I’ve just installed it on my local test site and it’s throwing up this error: “( ! ) Warning: Declaration of c2c_ConfigureSMTP::options_page_description() should be compatible with C2C_Plugin_023::options_page_description($localized_heading_text = ”) in C:\wamp64\www\test_site\wp-content\plugins\configure-smtp\configure-smtp.php on line 47″